Organic polymer/inorganic particles composite materials

ABSTRACT

The invention discloses a fire resistant composite material comprising inorganic particles well dispersed in a polymer having reactive functional groups. The inorganic particles also contain reactive functional groups, originally or after surface modification, that can react with the corresponding reactive functional groups of the polymer to form organic/inorganic composite materials. When the composite material is burned or under fire exposure, the polymer forms a char layer and the inorganic particles radiate absorbed heat. The inorganic particles also strengthen the mechanical properties of the structure through the reaction between inorganic and organic materials, so that the formed char layer is firm and can maintain its structural integrity without peeling off or cracks, effectively preventing direct heat transferring into the interior parts. The fire resistant material is not only flame retardant but also protective toward the interior materials. As a result, the duration of fire resistant ability is tremendously improved.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic polymer/inorganic particlescomposite material showing excellent fire resistant performance underflame sources or fire exposure. Within this composite system, both ofthe organic polymer and the inorganic particles contain reactivefunctional groups.

2. Description of the Related Art

Fire resistant or fire retardant materials can be used as thearchitecture or decorative materials. Architecture materials disclosedin TW 583,078 and TW 397,885 primarily comprise a stacked layer, servingas a fire resistant layer, made of nonflammable inorganic materials suchas pearlite (or perlite), MgCl₂, MgO, CaCO₃ or cement. In addition, astiff fire resistant laminate can be obtained from flexible substratesmade of fibers or nonwovens blended with flame retardants, foamingagents and 50˜80? inorganic materials by weight.

Fire resistant coatings, serving as decorative materials, disclosed inTW 442,549, TW 499,469 and TW 419,514 comprise a combination of foamingand intumescent agents, carbonization agents, flame retardants, andadhesives which foam and intumesce under fire exposure. U.S. Pat. No.5,723,515 discloses a fire-retardant coating material including a fluidintumescent base material having a foaming agent, a blowing agent, acharring agent, a binding agent, a solvent, and a pigment, increasingresistance to cracking and shrinking. A compound disclosed by U.S. Pat.No. 5,218,027 is manufactured from a composition of a copolymer orterpolymer, a low modulus polymer, and a synthetic hydrocarbonelastomer. The fire retardant additive comprising a group I, group II orgroup III metal hydroxide with the proviso that at least 1% by weight ofthe composition is in the form of an organopolysiloxane. U.S. Pat. No.6,262,161 relates to filled interpolymer compositions of ethylene and/oralpha-olefin/vinyl or vinylidene monomers, showing improved performanceunder exposure to flame or ignition sources, and fabricated articlesthereof. The articles are often in the form of a film, sheet, amultilayered structure, a floor, wall, or ceiling covering, foams,fibers, electrical devices, or wire and cable assemblies.

Specifically, as shown in FIGS. 1 a˜1 b, the heated area of a theconventional fire resistant material can be carbonized rapidly andexpand to 8˜10 times in volume greater than original due to the foaming,intumescent, and carbonization agents contained. However, as shown inFIGS. 1 c˜1 d, after long term heating, the intumescent carbonizationlayer (or the heated part) will slightly crack and peel off, thereforethe flame and heat can directly transfer to the interior materials andthe fire resistant ability will vanish. Accordingly, an improved fireresistant material is desirable.

BRIEF SUMMARY OF THE INVENTION

In view of the problems in the related art, the invention utilizes afire resistant composite material comprising various inorganic particleswell dispersed in a polymer having reactive functional groups. Theinorganic particles also contain reactive functional groups, originallyor after surface modification, so that can react with the correspondingreactive functional groups of the polymer to form organic/inorganiccomposite materials. Through the reaction between organic and inorganiccomponents, the mechanical and fire resistant properties of the organicpolymer are strengthened and enhanced. The organic polymer with reactivefunctional groups can be polyacid, polyurethane, epoxy, polyolefin,polyamine, polyimide, or derivatives thereof. The reactive functionalgroup can be epoxy group, —COOH, —NH₃, or —NCO. The preferred inorganicparticles comprise hydroxide, nitride, oxide, or metal salt which canreact with the functional groups of the organic polymer.

When the composite material is burned or under fire exposure, thepolymer forms a char layer and the inorganic particles radiate theabsorbed heat. The inorganic particles also strengthen the mechanicalproperties of the structure through the reaction between inorganic andorganic materials, so that the formed char layer on the surface is firmand can maintain its structural integrity without peeling off or cracks,effectively preventing direct heat transferring into interior parts. Thefire resistant material is not only flame retardant but also protectivetoward the interior materials. As a result, the duration of fireresistant ability is tremendously improved.

FIG. 3 is a flowchart demonstrating the processes of the organicpolymer/inorganic particles composite material. As shown in FIG. 3, adetailed description is given in the following embodiments withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more fully understood by reading thesubsequent detailed description and examples with references made to theaccompanying drawings, wherein:

FIGS. 1 a˜1 d are pictures showing conventional intumescent fireresistant materials subjected to a flame test;

FIG. 2 is a picture showing an organic polymer/inorganic particlescomposite material of the invention which is subjected to a flame test;

FIG. 3 is a flowchart demonstrating the synthesis processes of theorganic polymer/inorganic particles composite material; and

FIG. 4 is a schematic figure demonstrating the flame test for a sampleof the organic polymer/inorganic particles composite material.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best-contemplated mode of carryingout the invention. This description is made for the purpose ofillustrating the general principles of the invention and should not betaken in a limiting sense. The scope of the invention is best determinedby reference to the appended claims.

The organic polymer containing reactive functional groups (such asR—COOH) on main chains is mixed with solvents (such as water, alcohol,or MEK). Subsequently, inorganic particles with corresponding reactivefunctional groups (such as M-OH) are added to the polymer solution, andthe mixture is stirred at 70˜90? for 20 minutes to several hours tillthe reaction has completed. The slurry of R—COO⁻M⁺ is produced by meansof the reaction between R—COOH of the polymer and M-OH of the inorganicparticles, where R represents carbon chains and M represents metal. Acomposite sample layer is obtained by coating the slurry on a teflonsheet followed by drying and molding the slurry layer at elevatedtemperature. The sample layer can be rigid or flexible depending on theorganic/inorganic system of the composite. Each sample layer of thefollowing embodiments and comparative examples is prepared according tothe processes illustrated in FIG. 3. Finally, the sample layer is placedon a piece of A4 size paper and subjected to a flame test. Table 1 showsthe results of the flame test in different organic/inorganic systems.

First Embodiment

Poly(ethylene-co-acrylic acid) containing R—COOH was dissolved ordispersed in water. Subsequently, inorganic particles Al(OH)₃ withreactive functional groups M-OH were added to the polymer solution, andthe mixture was stirred at 70˜90 for 20 minutes. 1 mm-thick mixtureslurry was coated on a teflon sheet, and then placed in an oven, driedat 60? for 60 minutes, 80? for 60 minutes, 100? for 60 minutes, 120? for30 minutes, 140? for 30 minutes, 160? for 30 minutes, 180? for 30minutes, and finally, molded at 200? for 240 minutes.

As shown in FIG. 4, the sample layer 20 was removed from the teflonsheet (not shown), and placed on a piece of A4 size paper 10. A flametest was conducted on the surface of the sample layer 20 by butane gastorch 30 with flame temperature of 1000˜1200? (flame 40) for 30seconds˜3 minutes. The result of the burning phenomenon of the piece ofA4 size paper was summarized in table 1. There was no scorch observed onthe piece of A4 size paper after heating for 30, 60 and 120 secondswhile it became slightly scorched after heating for 180 seconds.

According to this embodiment, the duration of fire resistant ability was3 minutes due to the strengthened sample layer, i.e. R—COOH ofpoly(ethylene-co-acrylic acid) reacted with M-OH of Al(OH)₃ to formchemical bonds instead of physical blending.

Second Embodiment

Poly(ethylene-co-acrylic acid) containing R—COOH was dissolved ordispersed in water. Subsequently, inorganic particles Mg(OH)₂ withreactive functional groups M-OH were added to the polymer solution, andthe mixture was stirred at 70˜90 for 20 minutes. 1 mm-thick mixtureslurry was coated on a teflon sheet, and then placed in an oven, driedat 60? for 60 minutes, 80? for 60 minutes, 100? for 60 minutes, 120? for30 minutes, 140? for 30 minutes, 160? for 30 minutes, 180? for 30minutes, and finally, molded at 200? for 240 minutes.

As shown in FIG. 4, the sample layer 20 was removed from the teflonsheet (not shown), and placed on a piece of A4 size paper 10. A flametest was conducted on the surface of the sample layer 20 by butane gastorch 30 with flame temperature of 1000˜1200? (flame 40) for 30seconds˜3 minutes. The result of the burning phenomenon of the piece ofA4 size paper was summarized in table 1. There was no scorch observed onthe piece of A4 size paper after heating for 30, 60 and 120 secondswhile it became slightly scorched after heating for 180 seconds.

According to this embodiment, the duration of fire resistant ability was3 minutes due to the strengthened sample layer, i.e. R—COOH ofpoly(ethylene-co-acrylic acid) reacted with M-OH of Mg(OH)₂ to formchemical bonds instead of physical blending.

Third Embodiment

Poly(acrylic acid-co-maleic acid) containing R—COOH was dissolved ordispersed in water. Subsequently, inorganic particles Al(OH)₃ withreactive functional groups M-OH were added to the polymer solution, andthe mixture was stirred at 70˜90 for 20 minutes. 1 mm-thick mixtureslurry was coated on a teflon sheet, and then placed in an oven, driedat 60? for 60 minutes, 80? for 60 minutes, 100? for 60 minutes, 120? for30 minutes, 140? for 30 minutes, 160? for 30 minutes, 180? for 30minutes, and finally, molded at 200? for 240 minutes.

As shown in FIG. 4, the sample layer 20 was removed from the teflonsheet (not shown), and placed on a piece of A4 size paper 10. A flametest was conducted on the surface of the sample layer 20 by butane gastorch 30 with flame temperature of 1000˜1200? (flame 40) for 30seconds˜3 minutes. The result of the burning phenomenon of the piece ofA4 size paper was summarized in table 1. There was no scorch observed onthe piece of A4 size paper after heating for 30, 60 and 120 secondswhile it became slightly scorched after heating for 180 seconds.

According to this embodiment, the duration if fire resistant ability was3 minutes due to the strengthened sample layer, i.e. R—COOH ofpoly(acrylic acid-co-maleic acid) reacted with M-OH of Al(OH)₃ to formchemical bonds instead of physical blending.

Fourth Embodiment

Polyurethane containing R—NCO was dissolved or dispersed in hexane.Subsequently, inorganic particles Al(OH)₃ with reactive functionalgroups M-OH were added to the polymer solution, and the mixture wasstirred at room temperature for 20 minutes. 1 mm-thick mixture slurrywas coated on a teflon sheet, and then placed in an oven, molded at 60?for 120 minutes.

As shown in FIG. 4, the sample layer 20 was removed from the teflonsheet (not shown), and placed on a piece of A4 size paper 10. A flametest was conducted on the surface of the sample layer 20 by butane gastorch 30 with flame temperature of 1000˜1200? (flame 40) for 30seconds˜3 minutes. The result of the burning phenomenon of the piece ofA4 size paper was summarized in table 1. There was no scorch observed onthe piece of A4 size paper after heating for 30, 60 and 120 secondswhile it became slightly scorched after heating for 180 seconds.

According to this embodiment, the duration of fire resistant ability was3 minutes due to the strengthened sample layer, i.e. R—NCO ofpolyurethane reacted with M-OH of Al(OH)₃ to form chemical bonds insteadof physical blending.

FIRST COMPARATIVE EXAMPLE

Poly(ethylene-co-acrylic acid) containing R—COOH was dissolved ordispersed in water. Subsequently, inorganic particles SiO₂ were added tothe polymer solution, and the mixture was stirred at 70˜90 for 20minutes. 1 mm-thick mixture slurry was coated on a teflon sheet, andthen placed in an oven, dried at 60? for 60 minutes, 80? for 60 minutes,100? for 60 minutes, 120? for 30 minutes, 140? for 30 minutes, 160? for30 minutes, 180? for 30 minutes, and finally, molded at 200? for 240minutes.

As shown in FIG. 4, the sample layer 20 was removed from the teflonsheet (not shown), and placed on a piece of A4 size paper 10. A flametest was conducted on the surface of the sample layer 20 by butane gastorch 30 with flame temperature of 1000˜1200? (flame 40) for 30seconds˜3 minutes. The result of the burning phenomenon of the piece ofA4 size paper was summarized in table 1. When the flame contacted thesurface of the sample layer, the composite rapidly melted within severalseconds and then charred irregularly in 30 seconds. The nonuniform charhad lost its structural integrity due to the formation of cracks. Apiece of A4 size paper became slightly scorched after heating for 30seconds; scorched after heating for 60 seconds. Finally, the papersubstrate burned after heating for 120 seconds because of the majorityof cracks.

According to this comparative example, the duration of fire resistantability is less than 2 minutes because that R—COOH ofpoly(ethylene-co-acrylic acid) did not react with SiO₂ to form awell-structured composite by the formation of chemical bonds.

SECOND COMPARATIVE EXAMPLE

Poly(acrylic acid-co-maleic acid) containing R—COOH was dissolved ordispersed in water. Subsequently, inorganic particles Al₂O₃ were addedto the polymer solution, and the mixture was stirred at 70˜90 for 20minutes. 1 mm-thick mixture slurry was coated on a teflon sheet, andthen placed in an oven, dried at 60? for 60 minutes, 80? for 60 minutes,100? for 60 minutes, 120? for 30 minutes, 140? for 30 minutes, 160? for30 minutes, 180? for 30 minutes, and finally, molded at 200? for 240minutes.

As shown in FIG. 4, the sample layer 20 was removed from the teflonsheet (not shown), and placed on a piece of A4 size paper 10. A flametest was conducted on the surface of the sample layer 20 by butane gastorch 30 with flame temperature of 1000˜1200? (flame 40) for 30seconds˜3 minutes. The result of the burning phenomenon of the piece ofA4 size paper was summarized in table 1. When the flame contacted thesurface of the sample layer, the composite rapidly melted within severalseconds and then charred irregularly in 30 seconds. The nonuniform charhad lost its structural integrity due to the formation of cracks. Apiece of A4 size paper became slightly scorched after heating for 30seconds; scorched after heating for 60 seconds. Finally, the papersubstrate burned after heating for 120 seconds because of the majorityof cracks.

According to this comparative example, the duration of fire resistantability is less than 2 minutes because that R—COOH of poly(acrylicacid-co-maleic acid) did not react with Al₂O₃ to form a well-structuredcomposite by the formation of chemical bonds.

THIRD COMPARATIVE EXAMPLE

Polyurethane containing R—NCO was dissolved or dispersed in hexane.Subsequently, inorganic particles SiO₂ were added to the polymersolution, and the mixture was stirred at room temperature for 20minutes. 1 mm-thick mixture slurry was coated on a teflon sheet, andthen placed in an oven, molded at 60? for 120 minutes.

As shown in FIG. 4, the sample layer 20 was removed from the teflonsheet (not shown), and placed on a piece of A4 size paper 10. A flametest was conducted on the surface of the sample layer 20 by butane gastorch 30 with flame temperature of 1000˜1200? (flame 40) for 30seconds˜3 minutes. The result of the burning phenomenon of the piece ofA4 size paper was summarized in table 1. When the flame contacted thesurface of the sample layer, the composite rapidly melted within severalseconds and then charred irregularly in 30 seconds. The nonuniform charhad lost its structural integrity due to the formation of cracks. Apiece of A4 size paper became slightly scorched after heating for 30 to60 seconds; scorched after heating for 120 seconds. Finally, the papersubstrate burned after heating for 180 seconds because of the majorityof cracks.

According to this comparative example, the duration of fire resistantability is about 2 minutes because that R—NCO of polyurethane did notreact with SiO₂ to form a well-structured composite by the formation ofchemical bonds.

FOURTH COMPARATIVE EXAMPLE

Poly(vinyl alcohol) containing R—OH was dissolved or dispersed in water.Subsequently, inorganic particles Al(OH)₃ were added to the polymersolution, and the mixture was stirred at 70˜90 for 20 minutes. 1mm-thick mixture slurry was coated on a teflon sheet, and then placed inan oven, dried at 60? for 60 minutes, 80? for 60 minutes, 100? for 60minutes, 120? for 30 minutes, 140? for 30 minutes, 160? for 30 minutes,180? for 30 minutes, and finally, molded at 200? for 240 minutes.

As shown in FIG. 4, the sample layer 20 was removed from the teflonsheet (not shown), and placed on a piece of A4 size paper 10. A flametest was conducted on the surface of the sample layer 20 by butane gastorch 30 with flame temperature of 1000˜1200? (flame 40) for 30seconds˜3 minutes. The result of the burning phenomenon of the piece ofA4 size paper was summarized in table 1. When the flame contacted thesurface of the sample layer, the composite rapidly melted within severalseconds and then charred irregularly in 30 seconds. The nonuniform charhad lost its structural integrity due to the formation of cracks. Apiece of A4 size paper became slightly scorched after heating for 30seconds; scorched after heating for 60 seconds. Finally, the papersubstrate burned after heating for 120 seconds because of the majorityof cracks.

According to this comparative example, the duration of fire resistantability is less than 2 minutes because that R—OH of poly(vinyl alcohol)did not react with the M-OH of Al(OH)₃ to form a well-structuredcomposite by the formation of chemical bonds.

Due to the chemical bonding between the corresponding reactivefunctional groups of the organic polymer and the inorganic particles,the formed char layer on the surface is firm with excellent structuralintegrity and does not easily crack and peel off, effectively preventingdirect heat transferring into interior parts. The fire resistantmaterial is not only flame retardant but also protective toward theinterior materials. As a result, the duration of fire resistant abilityis tremendously improved.

While the invention has been described by ways of examples and in termsof the preferred embodiments, it can be understood that the invention isnot limited to the disclosed embodiments. To the contrary, it isintended to cover various modifications and similar arrangements (aswould be apparent to those skilled in the art). Therefore, the scope ofthe appended claims should be accorded the broadest interpretation so asto encompass all such modifications and similar arrangements. TABLE 1Results of the flame test of the organic polymer/inorganic particlescomposite materials Paper states after direct heating Organic Inorganicat 1000-1200° C. for polymer particles 30 secs. 1 min. 2 mins. 3 mins.poly Al(OH)₃ unchanged unchanged unchanged Slightly (ethylene- scorchedco-acrylic acid) poly Mg(OH)₂ unchanged unchanged unchanged Slightly(ethylene- scorched co-acrylic acid) poly SiO₂ Slightly Scorched burning— (ethylene- scorched co-acrylic acid) poly Al(OH)₃ unchanged unchangedunchanged Slightly (acrylic scorched acid-co- maleic acid) poly Al₂O₃Slightly Scorched burning — (acrylic scorched acid-co- maleic acid)polyure- Al(OH)₃ unchanged unchanged unchanged Slightly thane scorchedpolyure- SiO₂ Slightly Slightly Scorched burning thane scorched scorchedpoly Al(OH)₃ Slightly Scorched burning — vinyl scorched alcohol

1. An organic polymer/inorganic particles composite material,comprising: an organic polymer with a first reactive functional group;and inorganic particles, wherein the inorganic particles contains asecond reactive functional group originally or after surfacemodification.
 2. The organic polymer/inorganic particles compositematerial as claimed in claim 1, wherein the content of the organicpolymer is between 10˜90? by weight.
 3. The organic polymer/inorganicparticles composite material as claimed in claim 2, wherein the firstreactive functional group comprises epoxy group, —COOH, —NH₃, or —NCO.4. The organic polymer/inorganic particles composite material as claimedin claim 2, wherein the organic polymer comprises polyacid,polyurethane, epoxy, polyolefin, polyamine, polyimide, or derivativesthereof.
 5. The organic polymer/inorganic particles composite materialas claimed in claim 1, wherein the content of the inorganic particles isbetween 10˜90? by weight.
 6. The organic polymer/inorganic particlescomposite material as claimed in claim 5, wherein the inorganicparticles comprise hydroxide, nitride, oxide, or metal salt.
 7. Theorganic polymer/inorganic particles composite material as claimed inclaim 6, wherein the hydroxide comprises metal hydroxide.
 8. The organicpolymer/inorganic particles composite material as claimed in claim 7,wherein the metal hydroxide comprises Al(OH)₃ or Mg(OH)₂.
 9. The organicpolymer/inorganic particles composite material as claimed in claim 6,wherein the oxide comprises SiO₂, TiO₂, or ZnO.
 10. The organicpolymer/inorganic particles composite material as claimed in claim 6,wherein the nitride comprises BN.
 11. The organic polymer/inorganicparticles composite material as claimed in claim 6, wherein the metalsalt comprises CaCO₃.
 12. The organic polymer/inorganic particlescomposite material as claimed in claim 5, wherein the inorganicparticles comprise clay.
 13. The organic polymer/inorganic particlescomposite material as claimed in claim 12, wherein the clay comprisessmectite clay, vermiculite, halloysite, sericite, saponite,montmorillonite, beidellite, nontronite, mica, or hectorite.
 14. Theorganic polymer/inorganic particles composite material as claimed inclaim 5, wherein the inorganic particles comprise SiC.
 15. The organicpolymer/inorganic particles composite material as claimed in claim 5,wherein the inorganic particles comprise LDH.
 16. The organicpolymer/inorganic particles composite material as claimed in claim 5,wherein the inorganic particles comprise talc.
 17. The organicpolymer/inorganic particles composite material as claimed in claim 3,wherein the inorganic particles comprise Al(OH)₃ or Mg(OH)₂.
 18. Theorganic polymer/inorganic particles composite material as claimed inclaim 17, wherein the content of the organic polymer is between 10˜90?by weight.
 19. The organic polymer/inorganic particles compositematerial as claimed in claim 17, wherein the content of the inorganicparticles is between 10˜90? by weight.